Designing stable 2D materials solely from VIA elements

While the stability of tellurene is generally unsatisfactory among 2D materials, we show that elements from group-VIA may constitute stable 2D materials through the design principle of ionic bonding. In particular, a 2D wide-bandgap semiconductor, TeO3 monolayer with the CrI3-type crystal structure, has been predicted. High kinetic, thermodynamic, and mechanical stabilities have been confirmed by means of first-principles calculations. Remarkably, due to the van Hove singularities in the valence band electronic structures, TeO3 monolayer possesses tunable magnetism and half-metallicity with hole doping or elemental substitution. The corresponding Curie temperatures is above the room temperature according to the results of mean field approximation calculations. Furthermore, the carrier mobilities, exfoliation features, origin of high stability, and possible applications are discussed in detail. The TeO3 monolayer can serve as promising candidates for future nanoelectronics and spintronics applications. SeO3 and SO3 in the same 2D structure are also investigated.